The Red Queen Hypothesis

"Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!"

The Red Queen, Through the Looking-Glass, Lewis Carroll

One assumption investors stop questioning, stress-tested.

01The assumption

Valuations must revert to their historical mean. Multiples above the long-run average imply below-average returns ahead; the further above, the worse the reckoning deferred.

This is the most respectable assumption in investing — held not by the complacent but by the careful. Which is exactly why it belongs in this series: the framework stress-tests comfortable assumptions, and caution can be as comfortable as optimism.

02Why it's believed

Reversion to the mean is logical and intuitive. It rests on common sense, and it has a fine track record. And it comes twinned with the knowing scepticism that "this time is different" triggers in any intelligent investor.

Buying cheap has been rewarded across a century of data; good value correlates with good long-term returns — as it should. Every mania postmortem highlights the excess, with the same hindsight refrain: what were we thinking?

And yet, over a significantly long period — a career-defining one — the assumption has been an expensive error. Value and price are connected, but regime and environment move them both. There is a tension here, and the usual dose of cognitive dissonance.

This is where the stress test lives.

03The stress test — three questions the mean never faces

Whose mean? Environmental adaptation: survival of the fittest, where fitness means the capacity to adapt. This is not about averages; it is about change. Non-linear change, of the throw-out-the-textbook kind.

The "long-run average" stretching back a century aggregates economies that no longer exist — railways and industrials carrying their assets on the balance sheet, gold-standard and closed-capital-account regimes, interest rate environments from 15% to zero.

Today's index is dominated by asset-light businesses whose principal investments — research, software, brands — are expensed rather than capitalised, which depresses reported earnings and inflates the apparent multiple before any judgement about value begins.

Averaging today's market against that history could be a category error. The mean is not a law of nature; it is a description of a regime, and regimes move.

You've got to run twice as fast.

What has the assumption cost? Applied as a timing tool, more than the avoidance of most crashes returned — from a long-run P&L perspective, and ignoring the emotional cost.

The cyclically adjusted multiple has sat above its long-run average almost continuously since the early 1990s.

An investor who treated "above average" as a signal to stand aside has spent three decades waiting to be right, through one of the greatest compounding periods in market history.

The occasional vindications — 2000, 2008 — returned a fraction of what the waiting cost. An assumption can be directionally respectable and practically destructive at the same time; this one is the standing example.

Who does the reverting? This is the question that connects to where this series began.

Mean reversion is not gravity. It is work.

Performed by price-sensitive capital selling what is expensive and buying what is cheap, dragging prices toward some anchor of value. Entry 01 examined what is happening to that capital: its share of the market is shrinking year by year as price-insensitive flows grow. The same mechanism that made Entry 01 uncomfortable for the complacent makes this entry uncomfortable for the cautious.

With less of the market doing the anchoring, elevated valuations can persist — and stretch further — for far longer than any historical average implies. One mechanism, two directions. The framework does not care which consensus it inconveniences.

04The threshold condition

The assumption fails at a specific point of use: the moment reversion-to-the-mean is treated as a timing instrument rather than a long-horizon expectations input. Valuation retains genuine signal about returns over a decade. It carries approximately none about the next year. And the anchor it reverts to is set by the regime — the rate environment, the margin and tax structure, the accounting treatment of investment, and the share of the market still doing valuation work at all.

So the replacement question is not is this above average? It is: what regime supports this level — and what, specifically, would end it? Name the supports, and a slogan becomes a set of monitorable conditions. That conversion is the entire method of this series.

05What to watch

The supports of the current level, not the level. Real long-term rates (the denominator under every multiple), the corporate margin and tax structure, and the passive share of the market — Entry 01's variable, now doing double duty. Movement in the supports is information; the multiple alone is not.

Valuation used in its valid role. As a long-horizon expected-return input for allocation and sizing decisions — where its record is real — rather than as an entry or exit trigger, where its record is poor.

The machinery of reversion restarting. Sustained flows back toward price-sensitive strategies, widening dispersion between cheap and expensive, value spreads compressing because capital is closing them. Reversion resumes when the workers return to the job — that is observable, and it is the honest early signal the cautious are waiting for.

06One more thing

None of this retires valuation. At genuine extremes it has reasserted itself in every regime yet observed, and it remains the best single input into what the next decade returns. The claim is narrower: the mean is regime-dependent, reversion requires machinery, and an assumption held by careful people is still an assumption.

In Looking-Glass country, it takes all the running you can do just to stay in the same place. The mean has been running for a century. The investor standing still on it is going backwards.

Earlier entries in this series stressed the market's comfortable optimism. This one stresses its comfortable pessimism. The framework has no direction — that is precisely what makes it usable.